U.S. patent application number 15/008625 was filed with the patent office on 2016-08-11 for monitoring apparatus and method for an optical signal-to-noise ratio and receiver.
This patent application is currently assigned to FUJITSU LIMITED. The applicant listed for this patent is FUJITSU LIMITED. Invention is credited to Liang DOU, Zhenning TAO.
Application Number | 20160233955 15/008625 |
Document ID | / |
Family ID | 56567152 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160233955 |
Kind Code |
A1 |
DOU; Liang ; et al. |
August 11, 2016 |
MONITORING APPARATUS AND METHOD FOR AN OPTICAL SIGNAL-TO-NOISE
RATIO AND RECEIVER
Abstract
A monitoring apparatus and method for an optical signal-to-noise
ratio and a receiver, where the apparatus includes: a processing
unit configured to perform nonlinear processing on a pilot signal
in received signals, or on a pilot signal in received signals and
data signals in a predefined range neighboring the pilot signal;
and a calculating unit configured to calculate an optical
signal-to-noise ratio of the received signals according to a result
of the nonlinear processing. Complexity of calculation may be
lowered and accuracy of calculation of an optical signal-to-noise
ratio may be improved, thereby efficiently improving the
performance of the system.
Inventors: |
DOU; Liang; (Beijing,
CN) ; TAO; Zhenning; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJITSU LIMITED |
Kawasaki |
|
JP |
|
|
Assignee: |
FUJITSU LIMITED
Kawasaki
JP
|
Family ID: |
56567152 |
Appl. No.: |
15/008625 |
Filed: |
January 28, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B 10/0775
20130101 |
International
Class: |
H04B 10/079 20060101
H04B010/079; H04B 10/2513 20060101 H04B010/2513 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2015 |
CN |
201510068356.3 |
Claims
1. A monitoring apparatus for an optical signal-to-noise ratio,
comprising: a processing unit configured to perform nonlinear
processing on one of a pilot signal in received signals and the
pilot signal in the received signals and data signals in a
predefined range neighboring the pilot signal; and a calculating
unit configured to calculate an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing.
2. The apparatus according to claim 1, wherein the apparatus
further comprises: an estimating unit configured to estimate
residual dispersion in the received signals according to the pilot
signal in the received signals; and a compensating unit configured
to perform dispersion compensation on the data signals in the
received signals according to an estimation result of the residual
dispersion; and the calculating unit is configured to calculate
noise power according to the result of the nonlinear processing,
and calculate signal power according to a result of the dispersion
compensation to calculate the optical signal-to-noise ratio of the
received signals.
3. The apparatus according to claim 1, wherein the apparatus
further comprises: a determining unit configured to determine a
nonlinear parameter of the nonlinear processing; wherein a noise
parameter making a noise power spectrum density of the pilot
signals minimum is used as the nonlinear parameter of the nonlinear
processing.
4. The apparatus according to claim 3, wherein the nonlinear
parameter of the nonlinear processing has at least one of a
following information: nonlinear coefficient .gamma., lengths of
optical fiber spans in a transmission link and vectors of the
optical fiber spans.
5. A communication system, comprising a receiver which comprises
the monitoring apparatus for an optical signal-to-noise ratio as
claimed in claim 1.
6. A monitoring method for an optical signal-to-noise ratio,
comprising: performing nonlinear processing on one of a pilot
signal in received signals and the pilot signal in the received
signals and data signals in a predefined range neighboring the
pilot signal; and calculating an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing.
7. The method according to claim 6, wherein the method further
comprises: estimating residual dispersion in the received signals
according to the pilot signal in the received signals; and
performing dispersion compensation on the data signals in the
received signals according to an estimation result of the residual
dispersion; and the calculating an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing comprises: calculating noise power according to the
result of the nonlinear processing, and calculating signal power
according to a result of the dispersion compensation to calculate
the optical signal-to-noise ratio of the received signals.
8. The method according to claim 6, wherein the method further
comprises: determining a nonlinear parameter of the nonlinear
processing; wherein a noise parameter making a noise power spectrum
density of the pilot signals minimum is used as the nonlinear
parameter of the nonlinear processing.
9. The method according to claim 8, wherein the nonlinear parameter
of the nonlinear processing has at least one of a following
information: nonlinear coefficient .gamma., lengths of optical
fiber spans in a transmission link and vectors of the optical fiber
spans.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application relates to the subject matter of the
Chinese patent application for invention, Application No.
201510068356.3, filed with Chinese State Intellectual Property
Office on Feb. 10, 2015. The disclosure of this Chinese application
is considered part of and is incorporated by reference in the
disclosure of this application.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to the field of communication
technologies, and in particular to a monitoring apparatus and
method for an optical signal-to-noise ratio and a receiver.
[0004] 2. Description of the Related Art
[0005] Optical signal-to-noise ratio (OSNR) is an amount directly
associated with the performance of a system no matter in a
conventional optical communication system with direct detection or
in a coherent optical communication system. Hence, much attention
has been paid to the study of optical signal-to-noise ratio
monitoring technologies.
[0006] A conventional measurement method based on a definition of
OSNR relies on such conditions as that a noise power spectrum is
flat, and there exists a section of band in the spectrum that
contains noise but contains no signal. As the increase of an
optical communication capacity, a transmission length and
transmission rate of a coherent optical communication system are
greatly increased than before. More optical nodes will result in
more fluctuation in a spectral shape of a noise, and an assumption
that optical noises are uniformly distributed in a spectrum is
facing more challenges. And at the same time, as channel spacing is
greatly reduced, finding a band where signals may be neglected to
measure noise power becomes an impractical subject. Hence,
measurement of an OSNR in a coherent communication system becomes a
new hot spot of studies.
[0007] In a practical communication system, besides noises in a
transmission link itself, a noise introduced by a nonlinear effect
is also contained. As a correlation length of a nonlinear noise
itself is very short, view from a frequency domain, a power
spectrum of a noise introduced by the nonlinear effect is hard to
be differentiated from a white noise of the transmission link
itself. Hence, for a general OSNR monitoring method, an estimation
value of a noise will be overlarge, hence, an estimation value of
the corresponding OSNR will be relatively small, which is
disadvantageous to the estimation of the system performance of the
whole transmission link.
[0008] Currently, a nonlinear compensation algorithm based on
digital signal processing may be used to compensate for a nonlinear
noise, so as to improve the system performance.
[0009] It should be noted that the above description of the
background is merely provided for clear and complete explanation of
the present disclosure and for easy understanding by those skilled
in the art. And it should not be understood that the above
technical solution is known to those skilled in the art as it is
described in the background of the present disclosure.
SUMMARY
[0010] If the above existing nonlinear compensation algorithm is
used to process a nonlinear noise, complexity of the calculation
process is very high, and the practical operability is poor.
[0011] Embodiments of the present disclosure provide a monitoring
apparatus and method for an optical signal-to-noise ratio and a
receiver, in which by performing nonlinear processing on a pilot
signal in received signals, or on a pilot signal in received
signals and data signals in a predefined range neighboring the
pilot signal, and calculating an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing, no nonlinear processing is needed to be performed on
the whole received signals, complexity of calculation may be
lowered and accuracy of calculation of an optical signal-to-noise
ratio may be improved, thereby efficiently improving the
performance of the system.
[0012] According to a first aspect of the embodiments of the
present disclosure, there is provided a monitoring apparatus for an
optical signal-to-noise ratio, including: a processing unit
configured to perform nonlinear processing on a pilot signal in
received signals, or on a pilot signal in received signals and data
signals in a predefined range neighboring the pilot signal; and a
calculating unit configured to calculate an optical signal-to-noise
ratio of the received signals according to a result of the
nonlinear processing.
[0013] According to a second aspect of the embodiments of the
present disclosure, there is provided a receiver, including the
monitoring apparatus for an optical signal-to-noise ratio as
described in the first aspect of the embodiments of the present
disclosure.
[0014] According to a third aspect of the embodiments of the
present disclosure, there is provided a monitoring method for an
optical signal-to-noise ratio, including: performing nonlinear
processing on a pilot signal in received signals, or on a pilot
signal in received signals and data signals in a predefined range
neighboring the pilot signal; and calculating an optical
signal-to-noise ratio of the received signals according to a result
of the nonlinear processing.
[0015] An advantage of the embodiments of the present disclosure
exists in that by performing nonlinear processing on the pilot
signal in the received signals, or on the pilot signal in received
signals and data signals in a predefined range neighboring the
pilot signal, and calculating an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing, no nonlinear processing is needed to be performed on
the whole received signals, complexity of calculation may be
lowered and accuracy of calculation of an optical signal-to-noise
ratio may be improved, thereby efficiently improving the
performance of the system.
[0016] With reference to the following description and drawings,
the particular embodiments of the present disclosure are disclosed
in detail, and the principles of the present disclosure and the
manners of use are indicated. It should be understood that the
scope of the embodiments of the present disclosure is not limited
thereto. The embodiments of the present disclosure contain many
alternations, modifications and equivalents within the scope of the
terms of the appended claims.
[0017] Features that are described and/or illustrated with respect
to one embodiment may be used in the same way or in a similar way
in one or more other embodiments and/or in combination with or
instead of the features of the other embodiments.
[0018] It should be emphasized that the term "comprise/include"
when used in this specification is taken to specify the presence of
stated features, integers, steps or components but does not
preclude the presence or addition of one or more other features,
integers, steps, components or groups thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The drawings are included to provide further understanding
of the present disclosure, which constitute a part of the
specification and illustrate the preferred embodiments of the
present disclosure, and are used for setting forth the principles
of the present disclosure together with the description. It is
obvious that the accompanying drawings in the following description
are some embodiments of the present disclosure only, and a person
of ordinary skill in the art may obtain other accompanying drawings
according to these accompanying drawings without making an
inventive effort. In the drawings:
[0020] FIG. 1 is a schematic diagram of a structure of the
monitoring apparatus for an optical signal-to-noise ratio of
Embodiment 1 of the present disclosure;
[0021] FIG. 2 is a schematic diagram of transmission signals of
Embodiment 1 of the present disclosure;
[0022] FIG. 3 is a schematic diagram of a transmission codeword
time sequence and corresponding frequency spectrum densities of
Embodiment 1 of the present disclosure;
[0023] FIG. 4 is a schematic diagram of noise power spectrum
densities of received signals of Embodiment 1 of the present
disclosure;
[0024] FIG. 5 is a flowchart of a method for selecting an optimal
nonlinear coefficient .gamma. to perform nonlinear processing on a
pilot signal of Embodiment 1 of the present disclosure;
[0025] FIG. 6 is a flowchart of using the monitoring apparatus 100
for an optical signal-to-noise ratio to perform monitoring on an
optical signal-to-noise ratio of Embodiment 1 of the present
disclosure;
[0026] FIG. 7 is a schematic diagram of a structure of the receiver
of Embodiment 2 of the present disclosure;
[0027] FIG. 8 is a schematic diagram of a structure of the
communication system of Embodiment 3 of the present disclosure;
and
[0028] FIG. 9 is a flowchart of the monitoring method for an
optical signal-to-noise ratio of Embodiment 4 of the present
disclosure.
DETAILED DESCRIPTION
[0029] These and further aspects and features of the present
disclosure will be apparent with reference to the following
description and attached drawings. In the description and drawings,
particular embodiments of the disclosure have been disclosed in
detail as being indicative of some of the ways in which the
principles of the disclosure may be employed, but it is understood
that the disclosure is not limited correspondingly in scope.
Rather, the disclosure includes all changes, modifications and
equivalents coming within the terms of the appended claims.
Embodiment 1
[0030] FIG. 1 is a schematic diagram of a structure of the
monitoring apparatus for an optical signal-to-noise ratio of
Embodiment 1 of the present disclosure. As shown in FIG. 1, the
apparatus 100 includes: a processing unit 101 and a calculating
unit 102.
[0031] The processing unit 101 is configured to perform nonlinear
processing on a pilot signal in received signals, or on a pilot
signal in received signals and data signals in a predefined range
neighboring the pilot signal;
[0032] and the calculating unit 102 is configured to calculate an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing.
[0033] It can be seen from the above embodiment that by performing
nonlinear processing on the pilot signal in the received signals,
or on the pilot signal in received signals and data signals in a
predefined range neighboring the pilot signal, and calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, no nonlinear processing is
needed to be performed on the whole received signals, complexity of
calculation may be lowered and accuracy of calculation of an
optical signal-to-noise ratio may be improved, thereby efficiently
improving the performance of the system.
[0034] In this embodiment, the received signals are signals in an
optical communication system that are transmitted from a
transmission end and received at a receiving end after passing
through a transmission link. As the pilot signal is interpolated
into the received signals, the pilot signal is contained in the
received signals.
[0035] In this embodiment, the pilot signal interpolated into the
received signals may be a pilot signal sequence constituted
alternatively by positive and negative signals, and may also be
pilot signals at different frequencies at two polarization states,
and a manner of transmission of a pilot signal is not limited in
embodiments of the present disclosure.
[0036] FIG. 2 is a schematic diagram of transmission signals of
this embodiment. As shown in FIG. 2, the transmission signals
include pilot signals and data signals; wherein the data signals
are data that are actually transmitted, and are also referred to as
payload data.
[0037] In this embodiment, in order to obtain the pilot signal in
the received signals, after signals are received at a receiving
end, a location of the pilot signal in the received signals needs
to be determined. For example, frame synchronization may be
performed on the received signals, and the location of the pilot
signal in the received signals may be determined according to frame
structures of the transmission signals at a transmission end. And a
method for determining the location of the pilot signal in the
received signals is not limited in embodiments of the present
disclosure.
[0038] In this embodiment, the processing unit 101 may be
configured to perform nonlinear processing on the pilot signal in
the received signals, or on the pilot signal in the received
signals and the data signals in a predefined range neighboring the
pilot signal by using an existing method. For example, the
predefined range may be set according to an actual situation.
[0039] In this embodiment, the pilot signal is widened during
transmission due to a nonlinear effect in an optical fiber
transmission link. Thus, accuracy of calculation of the optical
signal-to-noise ratio may further be improved by performing
nonlinear processing by intercepting part of the data signals
including those neighboring the pilot signal.
[0040] In this embodiment, the calculating unit 102 is configured
to calculate the optical signal-to-noise ratio of the received
signals according to the result of the nonlinear processing. For
example, the calculating unit 102 is configured to calculate noise
power according to the result of the nonlinear processing, and
calculate signal power according to the data signals in the
received signals, so as to calculate the optical signal-to-noise
ratio of the received signals.
[0041] In this embodiment, the apparatus 100 may further
include:
[0042] an estimating unit 103 configured to estimate residual
dispersion in the received signals according to the pilot signal in
the received signals; and
[0043] a compensating unit 104 configured to perform dispersion
compensation on the data signals in the received signals according
to an estimation result of the residual dispersion;
[0044] and the calculating unit 102 is configured to calculate
noise power according to the result of the nonlinear processing,
and calculate signal power according to a result of the dispersion
compensation, so as to calculate the optical signal-to-noise ratio
of the received signals.
[0045] In this embodiment, the estimating unit 103 is configured to
estimate the residual dispersion in the received signals according
to the pilot signal in the received signals. For example, the
residual dispersion in the received signals may be estimated by
calculating delay differences between the pilot signals in the
pilot signal sequence.
[0046] In this embodiment, existing methods may be used for
calculating the noise power according to the result of the
nonlinear processing and calculating the signal power according to
the result of the dispersion compensation.
[0047] The methods for calculating the noise power, the signal
power and the optical signal-to-noise ratio of this embodiment
shall be illustrated below.
[0048] FIG. 3 is a schematic diagram of a transmission codeword
time sequence and corresponding frequency spectrum densities of
this embodiment. Assuming that noises are uniformly distributed in
a range of a band, the noise power is equal to a power spectrum
density of a noise multiplied by a spectrum width. As shown in FIG.
3, a length of the shadowed part denotes the spectrum width, and
the noise power may be obtained by multiplying the noise power
spectrum density of the received signals with the pilot signal
being nonlinearly processed by the spectrum width. In this
embodiment, in order to tolerate a certain frequency difference (or
a residual frequency difference), frequency spots of the pilot
signal may be expanded leftwards or rightwards by several frequency
spots.
[0049] In this embodiment, the calculation of the signal power is
selected to be performed at a time period of the data signals
(payload signals). This is because that several optical filters are
contained in the optical fiber transmission link, and as
attenuation of the pilot signal located on the frequency spot is
not equal to an average loss of the signals, the power of the pilot
signal is not equal to the power of the signals at the receiver
end, and the power obtained through calculation at the time period
of the data signals (payload signals) is equal to a sum of the
signal power and the noise power. Therefore, the signal power may
be obtained by combining the above noise power.
[0050] In this embodiment, after obtaining the noise power and the
signal power of the received signals, following Formula (1), for
example, may be used to calculate the optical signal-to-noise ratio
of the received signals:
OSNR=10*log10(S/n)-10*log10(12.5e9/Bandwidth) (1);
[0051] where, OSNR denotes the optical signal-to-noise ratio of the
received signals, S denotes the signal power, n denotes the noise
power, Bandwidth denotes a signal bandwidth, and 12.5e9 denotes a
numeral value used due to that noise power in a bandwidth of 12.5
GHz needs to be taken into account in the calculation of the OSNR;
however, the numeral value 12.5e9 may be adjusted according to a
particular bandwidth.
[0052] In this embodiment, if the pilot signals interpolated into
the received signals are pilot signals at different frequencies at
the two polarization states, noise power and signal power at the
two polarization states may be calculated respectively, so as to
obtain optical signal-to-noise ratios at the two polarization
states respectively.
[0053] In this embodiment, the apparatus 100 may further
include:
[0054] a determining unit 105 configured to determine a parameter
of the nonlinear processing; for example, a parameter making a
noise power spectrum density of the pilot signals minimum is taken
as the parameter of the nonlinear processing.
[0055] In this embodiment, the estimating unit 103, the
compensating unit 104 and the determining unit 105 are optional,
and are shown in dashed boxes in FIG. 1.
[0056] In this embodiment, if there exists a nonlinear noise, a
noise floor will be raised, and if a nonlinear compensation
algorithm is adopted, the nonlinear noise will be suppressed, and
the noise floor will also be lowered to a level of an amplified
spontaneous emission (ASE) noise. Therefore, an optimal parameter
of nonlinear processing may be simply and efficiently determined by
taking the parameter making a noise power spectrum density of the
pilot signal minimum as the parameter of the nonlinear
processing.
[0057] In this embodiment, the parameter of nonlinear processing
may be any parameter used for nonlinear processing. For example,
the parameter of the nonlinear processing is at least one of
nonlinear coefficient .gamma., lengths of optical fiber spans in a
transmission link and vectors of the optical fiber spans.
[0058] In this embodiment, description shall be given taking that
the parameter of the nonlinear processing is a nonlinear
coefficient .gamma. as an example.
[0059] FIG. 4 is a schematic diagram of noise power spectrum
densities of the received signals of this embodiment. As shown in
FIG. 4, noise power spectrum densities to which different nonlinear
coefficients .gamma. correspond are obtained by scanning, and a
nonlinear coefficient .gamma. to which a curve of a lowest noise
power spectrum density corresponds as an optimal nonlinear
coefficient .gamma., which is used for performing the above
nonlinear processing.
[0060] FIG. 5 is a flowchart of a method for selecting an optimal
nonlinear coefficient .gamma. to perform nonlinear processing on
pilot signals of this embodiment. As shown in FIG. 5, the method
includes:
[0061] step 501: setting an initial nonlinear coefficient .gamma.
for nonlinear processing;
[0062] step 502: performing nonlinear compensation according to the
nonlinear coefficient .gamma.;
[0063] step 503: calculating the noise power spectrum density PSDi
according to a result of the nonlinear compensation;
[0064] step 504: comparing the noise power spectrum density PSDi
with a previously calculated noise power spectrum density PSDi-1,
so as to judge whether the noise power spectrum density PSDi is
greater than or equal to the previously calculated noise power
spectrum density PSDi-1, entering into step 505 when
PSDi<PSDi-1, and entering into step 506 when
PSDi.gtoreq.PSDi-1;
[0065] step 505: changing the nonlinear coefficient .gamma., and
turning back to step 502; and
[0066] step 506: taking a nonlinear coefficient .gamma. used in
previously calculating noise power spectrum density PSDi-1 as the
optimal nonlinear coefficient .gamma..
[0067] FIG. 6 is a flowchart of using the monitoring apparatus 100
for an optical signal-to-noise ratio to perform monitoring on an
optical signal-to-noise ratio of this embodiment. As shown in FIG.
6, the received signals are respectively inputted into the
processing unit 101, the estimating unit 103 and the determining
unit 105; the processing unit 101 is configured to perform
nonlinear processing on the pilot signal in the received signals,
the estimating unit 103 is configured to estimate the residual
dispersion in the received signals according to the pilot signal in
the received signals, the determining unit 105 is configured to
take the parameter making a noise power spectrum density of the
pilot signal minimum as the parameter of the nonlinear processing,
and provide the determined parameter of the nonlinear processing to
the processing unit 101 for the nonlinear processing, the
compensating unit 104 is configured to perform dispersion
compensation on the data signals in the receives signals according
to a result of estimation of the residual dispersion by the
estimating unit 103, and the calculating unit 102 is configured to
calculate the noise power according to a result of the nonlinear
processing performed by the processing unit 101, and calculate the
signal power according to a result of the dispersion compensation
performed by the compensating unit 104, so as to calculate the
optical signal-to-noise ratio of the received signals.
[0068] It can be seen from the above embodiment that by performing
nonlinear processing on the pilot signal in the received signals,
or on the pilot signal in received signals and data signals in a
predefined range neighboring the pilot signal, and calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, no nonlinear processing is
needed to be performed on the whole received signals, complexity of
calculation may be lowered and accuracy of calculation of an
optical signal-to-noise ratio may be improved, thereby efficiently
improving the performance of the system.
Embodiment 2
[0069] An embodiment of the present disclosure further provides a
receiver, including a monitoring apparatus for an optical
signal-to-noise ratio, a structure and function of the monitoring
apparatus for an optical signal-to-noise ratio being identical to
those described in Embodiment 1, which shall not be described
herein any further.
[0070] FIG. 7 is a schematic diagram of a structure of the receiver
of Embodiment 2 of the present disclosure. As shown in FIG. 7, the
receiver 700 may include a central processing unit 701 and a memory
702, the memory 702 being coupled to the central processing unit
701. This figure is exemplary only, and other types of structures
may be used to supplement or replace this structure for the
realization of telecommunications functions or other functions.
[0071] As shown in FIG. 7, the receiver 700 may further include a
communication module 703, an input unit 704, a display 705, and a
power supply 706.
[0072] In an implementation, functions of the monitoring apparatus
for an optical signal-to-noise ratio may be incorporated into the
central processing unit 701. For example, the central processing
unit 701 may be configured to perform nonlinear processing on pilot
signal in received signals, or on pilot signal in received signals
and data signals in a predefined range neighboring the pilot
signal; and calculate an optical signal-to-noise ratio of the
received signals according to a result of the nonlinear
processing.
[0073] In this embodiment, the central processing unit 701 may
further be configured to estimate residual dispersion in the
received signals according to the pilot signal in the received
signals; and perform dispersion compensation on the data signals in
the received signals according to an estimation result of the
residual dispersion; and calculating an optical signal-to-noise
ratio of the received signals according to a result of the
nonlinear processing includes: calculating noise power according to
the result of the nonlinear processing, and calculating signal
power according to a result of the dispersion compensation, so as
to calculate the optical signal-to-noise ratio of the received
signals.
[0074] In this embodiment, the central processing unit 701 may
further be configured to determine a parameter of the nonlinear
processing; wherein a parameter making a noise power spectrum
density of the pilot signals minimum is taken as the parameter of
the nonlinear processing.
[0075] In this embodiment, the parameter of the nonlinear
processing is at least one of nonlinear coefficient .gamma.,
lengths of optical fiber spans in a transmission link and vectors
of the optical fiber spans.
[0076] In another implementation, the monitoring apparatus for an
optical signal-to-noise ratio and the central processing unit 701
may be configured separately. For example, the monitoring apparatus
for an optical signal-to-noise ratio may be configured as a chip
connected to the central processing unit 701, with functions of the
monitoring apparatus for an optical signal-to-noise ratio being
realized under control of the central processing unit 701.
[0077] In this embodiment, the receiver 700 does not necessarily
include all the parts shown in FIG. 7.
[0078] As shown in FIG. 7, the central processing unit 701 is
sometimes referred to as a controller or control, and may include a
microprocessor or other processor devices and/or logic devices. The
central processing unit 701 receives input and controls operations
of every components of the receiver 700.
[0079] The memory 702 may be, for example, one or more of a buffer
memory, a flash memory, a hard drive, a mobile medium, a volatile
memory, a nonvolatile memory, or other suitable devices. And the
central processing unit 701 may execute the program stored in the
memory 702, so as to realize information storage or processing,
etc. Functions of other parts are similar to those of the prior
art, which shall not be described herein any further. The parts of
the receiver 700 may be realized by specific hardware, firmware,
software, or any combination thereof, without departing from the
scope of the present disclosure.
[0080] It can be seen from the above embodiment that by performing
nonlinear processing on the pilot signal in the received signals,
or on the pilot signal in received signals and data signals in a
predefined range neighboring the pilot signal, and calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, no nonlinear processing is
needed to be performed on the whole received signals, complexity of
calculation may be lowered and accuracy of calculation of an
optical signal-to-noise ratio may be improved, thereby efficiently
improving the performance of the system.
Embodiment 3
[0081] An embodiment of the present disclosure further provides a
communication system. FIG. 8 is a schematic diagram of a structure
of the communication system of this embodiment. As shown in FIG. 8,
the communication system 800 includes a transmitter 801, an optical
fiber transmission link 802 and a receiver 803; wherein a structure
and functions of the receiver 803 are identical to those described
in Embodiment 2, which shall not be described herein any further.
The transmitter 801 and the optical fiber transmission link 802 may
have structures and functions of an existing transmitter and
optical fiber transmission link, and the structures and functions
of the transmitter and the optical fiber transmission link are not
limited in embodiments of the present disclosure.
[0082] It can be seen from the above embodiment that by performing
nonlinear processing on the pilot signal in the received signals,
or on the pilot signal in received signals and data signals in a
predefined range neighboring the pilot signal, and calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, no nonlinear processing is
needed to be performed on the whole received signals, complexity of
calculation may be lowered and accuracy of calculation of an
optical signal-to-noise ratio may be improved, thereby efficiently
improving the performance of the system.
Embodiment 4
[0083] An embodiment of the present disclosure further provides a
monitoring method for an optical signal-to-noise ratio,
corresponding to the monitoring apparatus for an optical
signal-to-noise ratio of Embodiment 1. FIG. 9 is a flowchart of the
monitoring method for an optical signal-to-noise ratio of this
embodiment. As shown in FIG. 9, the method includes:
[0084] step 901: performing nonlinear processing on a pilot signal
in received signals, or on a pilot signal in received signals and
data signals in a predefined range neighboring the pilot signal;
and
[0085] step 902: calculating an optical signal-to-noise ratio of
the received signals according to a result of the nonlinear
processing.
[0086] In this embodiment, the method for performing nonlinear
processing on the pilot signal in received signals, or on the pilot
signal in received signals and data signals in a predefined range
neighboring the pilot signal, and the method for calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, are identical to those
described in Embodiment 1, which shall not be described herein any
further.
[0087] It can be seen from the above embodiment that by performing
nonlinear processing on the pilot signal in the received signals,
or on the pilot signal in received signals and data signals in a
predefined range neighboring the pilot signal, and calculating an
optical signal-to-noise ratio of the received signals according to
a result of the nonlinear processing, no nonlinear processing is
needed to be performed on the whole received signals, complexity of
calculation may be lowered and accuracy of calculation of an
optical signal-to-noise ratio may be improved, thereby efficiently
improving the performance of the system.
[0088] An embodiment of the present disclosure further provides a
computer-readable program, wherein when the program is executed in
a monitoring apparatus for an optical signal-to-noise ratio or a
receiver, the program enables the computer to carry out the
monitoring method for an optical signal-to-noise ratio as described
in Embodiment 4 in the monitoring apparatus for an optical
signal-to-noise ratio or the receiver.
[0089] An embodiment of the present disclosure further provides a
storage medium in which a computer-readable program is stored,
wherein the computer-readable program enables the computer to carry
out the monitoring method for an optical signal-to-noise ratio as
described in Embodiment 4 in a monitoring apparatus for an optical
signal-to-noise ratio or a receiver.
[0090] The above apparatuses and methods of the present disclosure
may be implemented by hardware, or by hardware in combination with
software. The present disclosure relates to such a
computer-readable program that when the program is executed by a
logic device, the logic device is enabled to carry out the
apparatus or components as described above, or to carry out the
methods or steps as described above. The present disclosure also
relates to a storage medium for storing the above program, such as
a hard disk, a floppy disk, a CD, a DVD, and a flash memory,
etc.
[0091] The present disclosure is described above with reference to
particular embodiments. However, it should be understood by those
skilled in the art that such a description is illustrative only,
and not intended to limit the protection scope of the present
disclosure. Various variants and modifications may be made by those
skilled in the art according to the principles of the present
disclosure, and such variants and modifications fall within the
scope of the present disclosure.
* * * * *